A ski binding of this type is described generally in Austrian Pat. No. 320 493. The known construction describes a liquid, which is pressed by a piston into a further cylinder, in which an opposed piston is provided and is moved against a spring force. The forced arrangement of two cylinders, which are connected in series in the direction of the force and the piston is associated automatically with a larger material and work input, than if only one cylinder with one piston is provided. Even if such a solution is already known from German OS No. 1 578 901, in which the fluid is removed through a throttle opening which is constructed in the form of a hole, both solutions have the disadvantage that with the change of the compression of the medium, the release values of the ski binding also change. In other words: the change of the initial tension of the spring force brings about automatically a change of the release moment or of the release forces, wherein also the course of the release operation changes in relation to the adjusted strength of the release spring and the force of the entire damping system (cylinder, piston and throttle openings), which force depends on the release spring.
The purpose of the invention is now to provide a device of the above-mentioned type which will maintain the release value, at which the binding opens independently of the occurring impact forces, inventively constant.
The set purpose is inventively attained by the release value, at which the ski binding is released, being constant independently of the occurring impact forces, and by said value being determined by an enlarging or decreasing chamber which is provided in the binding-fixed structural part and which changes the cross section of the chamber, the limit of which enlarging or decreasing chamber is determined, viewed in the direction of movement of the member, by a snap-off edge on the inside wall of the binding-fixed structural part.
Due to the fact that in the binding-fixed structural part there is determined an exact point, upon the reaching of which the sole holders, which are loaded by the entire spring system--spring and damping device included--are released instantly, the set goal is satisfactorily attained for an exact value and in a simple manner. The necessary increased expense is, compared with conventional devices having a cylinder, small and at any rate less than a construction having two binding-fixed structural parts.
A particular preferable embodiment of the invention consists in, as is actually known, the binding-fixed structural part being a cylinder and the movable member being a piston which can be moved in a longitudinal direction of the cylinder and has preferably two openings, wherein the line of intersection of the rear side of the piston with the snap-off edge determines the limit value of conducting of the medium from the first into the second chamber of the cylinder. The construction of the binding-fixed structural part as a cylinder and of the movable member as a piston, is undoubtedly a simple and inexpensive, actually known solution. Due to the fact that inventively through the line of intersection of the rear side of the piston with the snap-off edge, the limit value for conducting of the medium from the first into the second chamber of the cylinder can be determined, the designer of such a binding receives with respect to determining the release value, both a clear teaching for the technical subject and also the possibility of determining with sufficient play these release values.
A preferable embodiment of the invention inventively consists of a substantially rectangular pressure plate of a uniform thickness being secured at the end of a piston rod which is associated in a conventional manner with the piston, said end being remote from said piston, which pressure plate extends transversely with respect to the longitudinal direction of the ski and also including a slide member and an adjusting screw which is associated with a spring, wherein the other end of the spring is supported on a support plate, which also closes off the front end of the cylinder, so that the spring and cylinder are arranged substantially parallel to one another and also parallel with respect to the longitudinal extent of the slide member.
A different embodiment of the invention is characterized by the snap-off edge and thus the intake opening of a bypass channel lying in the rest position of the piston approximately in the area of its front side or of the closed end of the cylinder. Thus, the start of the snapping-off feature can be determined.
A further inventive construction consists in the cross section of the bypass channel being constant starting with the snap-off edge or increasing continuously or having a form consisting of three sections one after the other, the first being a decreasing depth, the second being of a constant depth and the third being of a continuously enlarging depth, wherein on the two limits of the constant section and the adjoining two further sections, the cross section of which changes, there is provided an additional snap-off edge. The damping action can be controlled by this measure. Therefore, one can achieve that the damping action is reduced continuously with an increasing stroke, or that the course of the damping action changes in relation to the stroke.
A still further inventive construction consists in the slide member being constructed as a cylinder, which, but for an opening on its front side for receiving the adjusting screw, is closed and is closed off on its side, which is remote from said front side, by means of a binding-fixed support plate. The plate has supported thereon one end of a spiral spring, by the other end of which a support plate is loaded, wherein coaxially with respect to the longitudinal axis of the slide member the cylinder with the piston is arranged and the spiral spring surrounds the cylinder at a distance therefrom. The piston rod has at its end, which is remote from the piston, a retaining head which is held in a blind hole of the adjusting screw by means of a sleeve, which adjusting screw is rotatably supported through a conical flange or collar in a correspondingly shaped groove in the slide member, however nonmovably in the longitudinal direction of the slide member, and the support plate for the spring having a threaded hole therein, through which the initial tension of the spring can be adjusted by means of the thread on the adjusting screw received in the threaded hole. This construction will achieve a series connection of the spring and the damping device, without changing anything in the design of the basic principle of the damping device. At the same time, however, the advantage of a resilient arrangement which is connected in series is achieved.
A further development of this thought of the invention consists in securing on an outer surface and at approximately half the length of the cylinder, guideways which are offset at 120.degree. and are each provided with one opening extending in the longitudinal direction of the binding, which guideways terminate flush with the closed end of the cylinder. Each opening has one guide pin which is secured to the support plate extending therethrough, which guide pin has at its ends, which are remote from the support plate, a stop which is engageable with the associated sides of the guideways and co-determine the expanding region of the spring. As a result, a simple arrangement is produced, by which the stroke of the spring system can easily be determined.
To fix the position of the cylinder in longitudinal direction of the ski, it is furthermore provided that the cylinder has a mounting member on the outside of its closed front side and arranged off-center with respect to its own longitudinal axis. The mounting member has arranged thereon a locking hook which is pivotal through a limited range about a mounting-fixed hinge pin and is constructed approximately hammer-shaped, and which locking hook has an oval opening which extends normally therethrough, the ovality of which extends in the longitudinal direction of the locking hook. A support pin which is secured to the support plate is received in the oval opening, the diameter of which pin corresponds approximately with the smallest distance between the edges of the oval opening.
A further inventive solution consists in the cylinder being lengthened beyond the end of the bypass channel, which end faces the support plate. The chamber which is formed by the extension is filled with a gaseous medium, preferably air, and the original cavity of the cylinder with the piston therein is filled with a liquid. The two chambers are separated from one another by a floating piston, and the floating piston is loaded if desired by a spring. The initial tension of the spring can be regulated preferably and in a conventional manner by means of an adjusting screw. Since the gaseous medium which acts against the floating piston is compressed along a polytrope by forces which are produced by the piston and by means of the liquid, the course of the release operation depends in addition on the position of the floating piston which in this manner is moved in direction toward the support plate. In the case of great impacts which last only a short time, only a small amount of liquid will flow through the openings, so that in such cases the floating piston is moved more strongly in a direction toward the support plate than if a sufficient amount of time is available for the liquid to flow from the chamber in front of the piston into the chamber behind the piston. If the piston reaches the snap-off edge, here too the damping function which is applied by the liquid onto the sole holders suddenly stops.
A different inventive embodiment consists in the binding-fixed structural part being a damping housing which is self-contained and the movable member being a damping blade which is pivotal about a vertical axis. The inside of the damping housing is limited in one direction of its expansion by two curved surfaces, the curvature of which is determined by different radii which are drawn from the centerpoint of the axis, follow one another and have at least one step therebetween. In this arrangement, the use of a back-and-forth moving piston is not needed, so that forces which act in the longitudinal direction of the ski and which produce possible vibrations cannot be created. Since in this arrangement we deal with a swingable construction, the possible vibrations which are created by the swinging of the damping blade can be neglected with respect to the holding function of the binding.
A further development of this thought of the invention consists in a substantially cube-like bearing block being secured on the base plate in the region of the end thereof which is remote from the operating lever. The bearing block is located in the longitudinal direction of the ski outside of the damping housing traversely with respect to the longitudinal axis of the ski approximately on the longitudinal axis of the base plate. An adjusting screw engages the bearing block to determine the position of the damping blade relative to the damping housing. By changing the position, the stroke, according to which the resistance-free release of the sole holder is to occur, can be adjusted between predetermined limits.
A still further thought of the invention consists, in particular in this construction, of the damping blade having on the side which faces the cavity of the damping housing and in the area of its free end a substantially rectangular recess of uniform depth, with which communicates an opening which extends through the damping blade transversely with respect to the ski, and a small spring plate arranged in the recess, which spring plate closes off the end of the opening which terminates in the recess. The spring plate is preferably secured, for example, screwed to the bottom of the recess. This construction permits a simple and inexpensive construction of a check valve.
Further inventive characteristics, advantages and details of the invention will now be described more in detail with reference to the drawings illustrating several exemplary embodiments.